An external plunge grinding machine with control panel automation technique
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An external plunge grinding machine with control panel automation technique

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An external plunge grinding machine with control panel automation technique An external plunge grinding machine with control panel automation technique Document Transcript

  • International Journal of Electrical Engineering and Technology (IJEET), ISSN 0976 – 6545(Print), ISSN 0976 – 6553(Online) Volume 4, Issue 4, July-August (2013), © IAEME 197 AN EXTERNAL PLUNGE GRINDING MACHINE WITH CONTROL PANEL AUTOMATION TECHNIQUE BASED ON MITSUBISHI PLC SYSTEM 1 Arvind N. Nakiya, 2 Mahesh A. Makwana, 3 Ramesh R. Gajera 1 Department of Electrical Engineering, Nirma University, Ahmedabad, India 2 Department of Mechanical Engineering, SVNIT, Surat, India 3 Department of PHE&T, FPTBE, AAU, Anand, India ABSTRACT Automation is the process of handling various parameters of process like temperature, flow, level etc. without presence of responsible person. In industrial field, Automation and control have greatly improve in industrial manufacturing in the world Technological advancement in automation and control over the past decades have contributed greatly to improve the productivity of virtually all manufacturing industries throughout the world. In the development of automation controllers the trend has been to move towards soft controllers so as to provide better control, more flexibility and more reliability with intelligent diagnostics of machine faults. So industries have gradually moved from conventional relay logic control to programmable logic control and then to computerized numeric control. In this paper all the required control, induction and servo motor performance data with ladder logic programming will be taken to a personal computer via PLC for further analysis. Various results are obtained and discussed. Keywords: External plunge Grinding machine (EPG), Programmable Logic Control (P.L.C.), induction motors, Personal Computer (PC), Servo motor, variable frequency drives, voltage control 1. INRODUCTION Almost any production line, machine function or process can be automated using a PLC. The speed and accuracy of the operation can be greatly enhanced using this type of control system. The use of programmable logic controllers (PLCs) with power electronics in electric machines applications has been introduced in the manufacturing automation [1]. But the biggest benefit in using a PLC is the ability to change and replicate the operation or process while collecting and communicating vital information. Since there were problems related to large electrical panels with a number of electrical components and extensive wiring, people felt the need for software logic controllers? So they gave birth to Programmable Logic Controller (P.L.C) wherein the control logic INTERNATIONAL JOURNAL OF ELECTRICAL ENGINEERING & TECHNOLOGY (IJEET) ISSN 0976 – 6545(Print) ISSN 0976 – 6553(Online) Volume 4, Issue 4, July-August (2013), pp. 197-204 © IAEME: www.iaeme.com/ijeet.asp Journal Impact Factor (2013): 5.5028 (Calculated by GISI) www.jifactor.com IJEET © I A E M E
  • International Journal of Electrical Engineering and Technology (IJEET), ISSN 0976 – 6545(Print), ISSN 0976 – 6553(Online) Volume 4, Issue 4, July-August (2013), © IAEME 198 is developed in ladder diagram, a software logic control, with a number of inputs taken from the environment and generating the outputs, depending on the logic programmed, to the environment. This helped to control any machine sequence with small electrical panels, less number of electrical components and less wiring with more flexibility to change machine sequence. These fulfilled some of their needs but the desire to obtain software controlled automation with accuracy necessitated the development of Human Machine Interface (HMI). In order to have better control for positioning, controlled speed and quick reversal of direction of slide movement, servo and induction motors having less inertia, along with servo drives are interfaced with the HMI. The user based part program decoded by the HMI provides the desired graphical profile with the control being transferred to P.L.C. and drives as and when required [2]. 2. PROGRAMMABLE LOGIC CONTROLLER A programmable logic controller is a specialized computer. Since it is a computer, it has all the basic component parts contained in any other computer, a central processing unit, memory, input interfacing, and output interfacing. Fig.1: Block Diagram of PLC The block diagram of Programmable Logic Controller is shown in Fig.1 the processor is a solid state device designed to replace relays, timers, counter etc. The necessary voltage and current requirement for the internal working of the PLC is generated by the power supply. The field element is interfaced to the input or output section. Typical input or output section, typical input element are push buttons, limit switches, proximity switches, relay contacts, selector switches, thumb wheels etc. Typical output elements are solenoid valves relay coils, indicator lights LED display etc. Fig.3 shows PLC based control panel system for external plunge grinding machine. In this control panel system Mitsubishi Q series PLC is used.PLC controls all inputs and outputs. Wheel is fed directly into the work piece in external plunge grinding. In this paper external plunge grinding is used for bearing application [2]. Fig.2: Block Diagram of experimental set up
  • International Journal of Electrical Engineering and Technology (IJEET), ISSN 0976 – 6545(Print), ISSN 0976 – 6553(Online) Volume 4, Issue 4, July-August (2013), © IAEME 199 A flowchart is ideal for a process that has sequential process steps. The steps will be executed in a simple order that may change as the result of some simple decisions. The symbols used for flowcharts are shown in Figure2. These blocks are connected using arrows to indicate the sequence of the steps. The different blocks imply different types of program actions. Fig.3: PLC based control panel for EPG 3. OPERATION OF SERVO MOTOR Ac servo motors are used in ac servomechanisms and computers which require rapid and accurate response characteristics. To obtain these characteristics, servo motors have small-diameter high-resistance rotors. The small diameter provides low inertia for fast starts, stops, and reversals, while the high resistance provides a nearly linear speed-torque relationship for accurate control. Servo motors are wound with two phases physically at right angles or in space quadrature. Servo motors feature a fixed or reference winding is excited from a fixed voltage source, while the control winding is excited by an adjustable or variable control voltage, usually from a servo amplifier. The servo motor windings are usually designed with the same voltage-turns ratio. Fig.4: A. C. Servo motor of EPG machine So that power inputs at maximum fixed-phase excitation and at maximum control-phase signal are in balance. In an ideal servo motor, torque at any speed is directly proportional to the servo motor's control winding voltage. In practice, however, this relationship exists only at zero speed because of the inherent inability of an induction servo motor to respond to voltage input changes
  • International Journal of Electrical Engineering and Technology (IJEET), ISSN 0976 – 6545(Print), ISSN 0976 – 6553(Online) Volume 4, Issue 4, July-August (2013), © IAEME 200 under conditions of light load. The inherent damping of servo motors decreases as ratings increase and the servo motors have a reasonable efficiency at the sacrifice of speed-torque linearity. Fig.5: Servo motor wiring As sown in fig 6 sequence of operation of servo motor is as below Step 1: Start Operation / Zero Position A If Push Button Start OPR = ON Then JOG = ON (Manual Operation to LS Zero) B If LS Zero = ON Then Start OPR = ON in Positioning Module QD75M1 C Waiting Servo to Positioning Operation Complete Step 2: Positioning Start A If Push Button Start = ON Then Positioning Start No.1 = RUN (To 20mm) And Waiting Positioning Complete. B If Positioning Complete = ON Then Positioning Start No.2 = RUN (To 40mm) And Waiting Positioning Complete. In this project used two servo motors, One for X-axis and other for y-axis. The capacity or x-axis motor is three phase, 123V, 6A, 1KW, and 2000rpm and for y-axis is three phase, 146V, 17A, 3.5KW, and 2000rpm. Fig.6: Operation of servo motor
  • International Journal of Electrical Engineering and Technology (IJEET), ISSN 0976 – 6545(Print), ISSN 0976 – 6553(Online) Volume 4, Issue 4, July-August (2013), © IAEME 201 4. VFD CONTROL The circuit shown in fig.7 is control the direction of rotation and speed of 3-phase induction motor by using VFD.230 V, 50Hz, 1 Phase supply is given across NO contact of relay(terminal A and C of VFD) Terminal SD is Common to the contact input terminal and terminal FM. Common output terminal for 24VDC 0.1A power output. SD terminal is connected to the selector switch 1. Terminal R, S, T is used as input and U, V, W is used as output which is connected to motor. In this there are two control methods (1) control by Auto (2) Control by Manually. In manually control, selector switch2 is connected across STF and STR terminal of VFD which is used for changing direction of rotation.1W, 2K ohm frequency setting potentiometer is connected across terminal 10, 2, 5 of VFD which is used to adjust input voltage and frequency setting of inverter. In automatic control we push the start forward push button on SCADA, relay R3 is energized and motor rotate in forward direction and pushing start reverse button on SCADA ,relay R4 is energized and motor rotate in reverse direction. Speed of motor is control by Analog output of PLC. Servo drives are used in conjunction with servo motors for better variable speed control with less response time as the inertia of the rotor is less [3]. Fig 8 sows how servo drive is connected with PLC. For this connection servo amplifier is connected between servomotor and PLC. Fig.7: VFD control wiring Fig.8: Servo drive connection 5. PROGRAMMING AND COMMUNICATION 5.1 Ladder Program The ladder program is then executed rung-by-rung. Scanning the program and solving the logic of the various ladder rungs determine the output states. The updated output states are stored in fixed memory locations (output image memory Q). The output values held in memory are then used to set and reset the physical outputs of the PLC simultaneously at the end of the program scan [4]. The host computer provides the software environment to perform file editing, storage, printing, and program operation monitoring. The process of developing the program to run on the PLC consists of: using an editor to draw the source ladder program, converting the source program to binary object code which will run on the PLC’ s microprocessor and downloading the object code from the PC to the PLC system via the serial communication port [5].
  • International Journal of Electrical Engineering and Technology (IJEET), ISSN 0976 – 6545(Print), ISSN 0976 – 6553(Online) Volume 4, Issue 4, July-August (2013), © IAEME 202 Here in this experimental set up work, the inputs and outputs selection are given below. Inputs X20-Gauge out X2E-Single cycle X21-Gauge in X2F-Multi cycle X22-Loader in X30-Auto dressing PB X23-Loader out X31-Wheel on/off X24-Loader up X32-W/H on/off X25- Magnet on/off X33- Loader down X26-Un loader down X34-Gauge in/out PB X27-Un loader up X35-Diamond roll on/off X28-Un loader in X36-Rough end IP X29-Un loader out X37-Finish end IP X2A-Oil level ok X38-Cycle end IP X2B-Oil PS X39-Un loader in/out PB X2C-Size +PB X3A-Loader up/down PB X2D-Size -PB X3B-Un loader up/down PB Outputs Y41-Wheel Y4E-Break release Y42-Work head Y4F-Oil lamp Y43-Diamond roll motor Y50-Homing lamp Y44-Lubrication motor Y51-Loader ok lamp Y45-Magnet Y52-Loading lamp Y46-Demagnetizer Y53-Alarm lamp Y47-Coolant Y54-Cycle lamp Y48-Loader down Y55-Yellow lamp Y49-Un loader up Y56-Red lamp Y4A-Loader out Y57-Gauge end valve Y4B-Un loader out Y58-Gauge start Y4C-Job clamp valve Y59-Gauge return Y4D-Job stop valve Fig 9 shows, how induction motor control through ladder logic programing by PLC. Initially I0 status bit is a logic because the normally closed (NC) stop pushbutton is closed I0.2 status bit is a logic because the normally closed (NC) overload relay (OL) contacts are closed I0.0 status bit is a logic 0 however because the normally open start pushbutton has not been pressed. Normally open output Q0.0 contact is also programmed on network as a sealing contact. With this simple network energizing output coil Q0.0 is required to turn on the motor. When the start pushbutton is pressed the CPU receives logic from input I0.0. This causes the I0.0 contact to close. All three inputs are now logic. The CPU sends logic to output Q0.0. The motor starter is energized and the motor starts. Fig.9: Motor Starts
  • International Journal of Electrical Engineering and Technology (IJEET), ISSN 0976 – 6545(Print), ISSN 0976 – 6553(Online) Volume 4, Issue 4, July-August (2013), © IAEME 203 5.2 Communication between PLC and computer The RS-232 standard is based on a low/false voltage between +3 to +15V, and an high/true voltage between -3 to -15V (+/-12V is commonly used).Fig 10 shows some of the common connection schemes. In all methods the txd and rxd lines are crossed so that the sending txd outputs are into the listening rxd inputs when communicating between computers. When communicating with a communication device (modem), these lines are not crossed. In the modem connection the dsr and dtr lines are used to control the flow of data. In the computer the cts and rts lines are connected. These lines are all used for handshaking, to control the flow of data from sender to receiver. The null-modem configuration simplifies the handshaking between computers. The three wire configuration is a crude way to connect to devices and data can be lost. Many PLC processors have an RS-232 port that is normally used for programming the PLC. Fig.10: Common RS-232 Connection Schemes For man machine interface LCD as shown in fig.11 is used. Fig.11: LCD Screen 6. RESULTS Many PLC processors have an RS-232 port that is normally used for programming the PLC. In Fig 12 Mitsubishi Q series PLC is connected with personal computer. For operation of machine required data for user is store as a form of programme in the PLC via PC. In programming result Fig 13 sows that in ladder rung 262, NO contact start, with contact MO, M7 and input X25, magnet is on/off. Similarly in fig 14 sows at rung 218, with loader out input contact X29, after 10S, loader is out.
  • International Journal of Electrical Engineering and Technology (IJEET), ISSN 0976 – 6545(Print), ISSN 0976 – 6553(Online) Volume 4, Issue 4, July-August (2013), © IAEME 204 Fig.12: Mitsubishi PLC with PC Fig.13: Experimental result for magnet on/off Fig.14: Experimental result for loader out 7. CONCLUSION After the above discussion we can conclude that by automation of PLC panel of EPG machine we can improve the Productivity in the industry. Also it is faster and more efficient than the classical techniques. By automation of PLC panel we continuously monitor the state of input devices and makes Decisions based upon a custom program to control the state devices connected as Output. REFERENCES [1] G. Kaplan, Technology 1992 Industrial electronics, IEEE Spectre. Vol. 29, pp. 47–48, Jan. 1992. [2] Arvind N. Nakiya, Mahesh A. Makwana, An Overview of PLC Based Control Panel System for External Plunge Grinding Machine and CNC Machine, International Journal of Modern Engineering Research, Vol.2, Issue.6, Nov-Dec. 2012. [3] Douglas V. Hall, Microprocessors and Interfacing (Programming and Hardware), Tata McGraw-Hill, 1992. [4] Mrs.Jignesha Ahir,Viren Pandya, and Chintan Mehta, Design and Development of PLC and SCADA Based Control Panel for Continuous Monitoring of 3-Phase Induction Motor, National Conference on Recent Trends in Engineering & Technology at B V M college, V.V.Nagar,Gujarat,India, 13-14 May 2011. [5] Yasar birbir, H.Selcuk Nogay, Design and Implementation of PLC-Based Monitoring Control System for Three-Phase Induction Motors Fed by PWM Inverter International Journal Of Systems Applications, Engineering & Development, Issue 3, Volume 2, 2008.